[feaLib.parser] Parse a feature file with only comments

Lib/fontTools/feaLib/parser.py

@@ -47,7 +47,7 @@ class Parser(object):
 
     def parse(self):
         statements = self.doc_.statements
-        while self.next_token_type_ is not None:
+        while self.next_token_type_ is not None or self.cur_comments_:
             self.advance_lexer_(comments=True)
             if self.cur_token_type_ is Lexer.COMMENT:
                 statements.append(self.ast.Comment(self.cur_token_location_, self.cur_token_))

Tests/feaLib/lexer_test.py

@@ -9,6 +9,7 @@ import unittest
 def lex(s):
     return [(typ, tok) for (typ, tok, _) in Lexer(s, "test.fea")]
 
+
 class LexerTest(unittest.TestCase):
     def __init__(self, methodName):
         unittest.TestCase.__init__(self, methodName)

Tests/feaLib/parser_test.py

@@ -86,6 +86,15 @@ class ParserTest(unittest.TestCase):
         self.assertEqual(c2.text, "# simple")
         self.assertEqual(doc.statements[1].name, "test")
 
+    def test_only_comments(self):
+        doc = self.parse("""\
+            # Initial
+        """)
+        c1 = doc.statements[0]
+        self.assertEqual(type(c1), ast.Comment)
+        self.assertEqual(c1.text, "# Initial")
+        self.assertEqual(str(c1), "# Initial")
+
     def test_anchor_format_a(self):
         doc = self.parse(
             "feature test {"